Previewing Modeled Content in the Portal 
Visual Composer provides a preview capability for modeled portal content, which enables you to see how your models appear and behave in the portal without leaving the modeling environment. You can then make changes based on behavior in the runtime environment.
Prerequisites
The user who is modeling in Visual Composer is assigned, in the portal, to the VC Dev Preview role by the portal administrator
Users not assigned to the VC Dev Preview role can preview iViews and pages but cannot preview other modeled content, such as roles and worksets, and cannot preview dynamic URL iViews or object-based navigation (OBN).
NoteWhen assigning users to the VC Dev Preview role in the portal Identity Management tool, search for the role ID and not its name. The ID of the VC Dev Preview role is
pcd:portal_content/com.sap.pct/com.sap.portal.modeling.generation.modeled_content/com.sap.portal.modeling.generation.vc_dev_preview
End of the note.
Models to be previewed have been deployed to the portal as described in Deploying Modeled Portal Content.
Procedure
In the Deploy task panel, expand a deployed development component and click the link of the model you want to preview.
Result
The portal opens in a separate window, displaying the portal object based on the selected model. You can go back to the model on the Portal Layout board, make changes, redeploy it, and preview it again.